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Robert Unsworth, GEA head of sales (utilities) in the UK, believes advances in heat pump technology can revolutionise refrigeration in the food sector.

The global trend of increased manufacturing; more stringent emission regulations and focus on maximizing efficiency brings with it new challenges for food processing. Having been in the refrigeration business for 25 years and seen minor changes, I can say that the application of heat pumps into the food sector, as well as the dairy and beverage sectors, is going to be the biggest leap forward food production and refrigeration has ever seen.

There really is no down side to employing heat pumps and all factories should be looking at using the technology.

​I have yet to see a food process where there is not enough heat to reuse and supply to another process. After all, it’s the same amount of heat put in to heat something up as is removed to cool it down again. The refrigeration plant is also removing heat from the building, people, lights, machinery motors and even the environment when you leave the door open in a chill room.

Yet all this heat is thrown away by the refrigeration system’s condenser, typically located not far from the boiler stack where you made some of it in the first place. Even at home, the heat we remove from our warm beer as we put it in the fridge is rejected out of the back to warm the kitchen.

The RedAstrum heat pump is basically a chiller, which, instead of rejecting the heat into the outside air at +30°C, rejects it into water, heating it to +65°C or hotter for example, recovering all the energy. Typically the capital cost of this will be similar to a boiler so there is no reason for a heat pump, combined with a refrigeration system, to not be considered in all new plants.

A heat pump transfers heat from a lower temperature level to a desired higher temperature level and is a far more eco-friendly and profitable solution than traditional heating alternatives. Industry, municipalities and homeowners have been using heat pumps for heating applications for many years already. However, it is only now that they are being incorporated into food processing procedures. New advances mean GEA heat pumps are now able to meet the required temperatures for food processing which makes food production more cost-effective and sustainable.

Heat pumps can be used in numerous industrial processes, given that plants have both waste heat flows (e.g. wastewater, hot humid air, condenser heat from refrigeration systems) and heat consumers (e.g. process water, central heating systems, blanchers, dryers, etc.) In view of this, most modern industries perform pinch analysis to map their heat flows and capacities, temperature levels, flow connection and interchange options to determine the suitability and ROI of a heat pump installation.

While heat pumps and the food industry have not traditionally been associated with one another, this trend is changing, as the technology develops and customers recognise the financial and environmental benefits of using heat pumps in their production processes, such as during slaughtering, cutting, drying, frying, chilling, portioning and packaging — all of which require both the application of heat during preparation and subsequent chilling.

Pushing down production costsTraditionally, a boiler was used in food processing to heat up or cook the food. The food was then put into a refrigerator to cool. However, this leads to huge amounts of energy being wasted as the temperature of the waste heat from the refrigeration process is too low to be reused. A GEA RedAstrum ammonia heat pump boosts the temperature of the waste heat up to 70/85 degrees and puts it back into the system – reusing the heat and making a boiler no longer necessary in some cases. Ammonia is readily available, inexpensive and has a minimal environmental impact. Although noxious at high concentrations, the implementation of carbon absorbers in ammonia-based heat pumps eliminates any risk. As well as significantly reducing the plant’s energy usage, the new system can lower water and chemical consumption from the site’s cooling towers, and as it is based on an industrial screw compressor, it has no additional service and maintenance requirements over a standard industrial chiller, unlike piston compressor based heat pumps.

GEA has installed heat pumps for many giants in the food industry, helping customers to reduce their running costs and CO2 emissions from day one. For example, a boiler and power supply in one customer’s plant consumed a total of 15.3 million kWh for heating and refrigeration combined in one year; which amounts to the release of 4,739 tonnes of CO2 into the atmosphere. By comparison, after installing GEA heat pumps, the combined usage was just 4.8 million kWh, producing 1,978 tonnes of CO2. That equates to a reduction in power consumption by 68.6% and a lowering of CO2 emissions by 58.2% – an attractive technology for companies struggling to reach their sustainability targets.

GEA holds vast amounts of process knowledge, with specialists in all areas. We combine this knowledge to create the best overall solution for a customer. Heat is heat, whether it is at -40 or +140°C, and GEA is really good at moving heat around. We should stop throwing it away and paying to do so.